The Red Knot (Calidris canutus) is a shorebird, roughly the size of an American Robin, and similarly colored in spring, with rusty red underparts and a ruddy brownish back sprinkled with black and calico. This species’ legacy has been punctuated by eras of superabundance, intense market hunting persecution, habitat disruption, and most recently anthropogenic events that have nearly brought the Atlantic flyway population to its knees. Favored sandy beaches on the South Shore of Cape Cod Bay and outer Cape Cod in Massachusetts have for many decades hosted great numbers of “Robin Snipes” (so-called by early market gunners) during their autumn migration en route to the far reaches of southern South America for the winter. And it was on these same Bay State beaches that the Atlantic population of knots was mercilessly persecuted from July-October during much of the 19th and early 20th century.
Fast forward to the last half of the 20th century when the ornithological community, initially in the Mid-Atlantic Coast region, began systematically registering measurable declines in the vast numbers of knots that once stopped on Massachusetts shores during autumn migration and on the shores of Delaware Bay in May. These early warnings presaged what was to become one of the most precipitous declines in modern shorebird history. The sad and well-documented chronicle of the near collapse of the eastern North American Red Knot population is one of the most dramatic sagas in modern-day bird conservation.
The pathos and intimate details of this ongoing conservation drama have recently been eloquently presented in Orion magazine by author and Audubon A awardee Deborah Cramer and artist Janet Essley. To explore the details of this fascinating story, follow this link >
The final report describing “Barn Swallow Nesting Biology at Bri Mar Stable, Hadley, Massachusetts During 2019” is available here. The report, written by Mass Audubon’s Director of Bird Conservation, Jon Atwood, as well as collaborators with the U.S. Fish and Wildlife Service, describes the scientific context and behavioral ecology of Barn Swallows nesting at the Fort River Division of the Silvio O. Conte National Fish and Wildlife Refuge.
In Mass Audubon’s formal response to the proposed demolition of an abandoned horse stable that is used by a large colony of nesting Barn Swallows, we wrote “If the barn does indeed need to be demolished in the near future, Mass Audubon supports the Refuge’s proposed action, Alternative A – Phased Closure of Stable and Delayed Demolition. We encourage the U.S. Fish and Wildlife Service to use the opportunities available under Alternative A to study methods that can be used to promote colony relocation on private and public lands. We also support monitoring of Barn Swallows on and around the site during the phased closure process. Mass Audubon’s bird conservation staff are willing to advise and support the refuge staff in those efforts.” This report is the result of this promised research effort.
The report provides useful data that is relevant to decisions regarding future plans of the refuge. There is no doubt that this site hosts a large colony of this declining species. However, multiple authors have pointed out that factors other than availability of nest sites are most likely responsible for the species’ regional population declines, and have even noted that small colonies often have higher reproductive success than large nesting groups. In 2019 we had good success in attracting swallows to nest in an adjacent structure where they can be protected in the future. And, we also discovered other nearby Barn Swallow colonies, including at least one site that is probably comparable in size to the colony at Bri Mar Stable.
We’ll keep you posted as we learn more about this ongoing
Errata: After we published the final report about Barn Swallow nesting biology at Bri Mar Stable, we discovered information about past nesting activity within the Boat House. These sentences, found in the Abstract and Results sections of the report, have been corrected.
“Species extinctions have defined the global biodiversity crisis, but extinction begins with loss in abundance of individuals” —Rosenberg et al., Decline of the North American Avifauna (2019)
So begins the first comprehensive review of bird population trends since the mid-20th century. Summaries of the study are available via the New York Times and NPR.
The results were unequivocal: 76% of all bird species in the US are declining, some precipitously. Compiling on-the ground data from Breeding Bird Atlases revealed that the total number of birds in the US has fallen by 29% since 1970. Some groups fared worse than other over the five decades in question: shorebirds were down 37%, warblers were down by 33%, and aerial insectivores were down by 32%. And the total volume of birds in the sky, as detected by the national weather radar, was down 14% in the last ten years alone.
This is bad news. Really bad news. But it’s possible to fight, and it’s even reversible. Scientists and conservation professionals have time-tested and proven strategies for stemming the tide of ecological decline, and the only obstacles are funding, public interest, and political will.
Mass Audubon continues to take a multi-pronged, species-specific approach to mitigate the damage in our state. Here are a few of the solutions we’ve already mobilized:
Birds simply can’t exist without bird habitat. We protect 36,000
acres of bird habitat in Massachusetts through direct ownership, and another
6,000 through “conservation restrictions” and other legal protections against
We’ve recorded 149 species of bird breeding & raising their young on our wildlife sanctuaries– over two thirds of the total species in the state.
Where we can’t protect land through direct purchase, we find
ways to ensure that it’s being used in bird-friendly ways. Many grassland
species have healthy populations on agricultural land, and agricultural
practices can make or break their prospects for survival. The same goes for
forest birds living on land actively managed for timber; birds and forestry can
coexist where sustainable practices are applied.
Mass Audubon encourages bird-friendly agriculture through
projects like the Bobolink Project,
incentivizing landowners to delay mowing hayfields until after Bobolinks and
other grassland birds have completed nesting. The project compensates
landowners directly for any profits lost due to delayed mowing, and the
compensation fund is 100% donor-supported. In 2018, we saved
more than 1,000 Bobolink fledglings from going under the mower.
Foresters for the Birds program pushes a bird-friendly approach to forestry
in Massachusetts. One of our sanctuaries even acts as a demonstration
site for how sustainable forestry and bird habitat go hand in hand.
Direct Habitat Management
Mass Audubon is directly responsible for managing between
40-50% of Piping Plovers (a federally Endangered species) in Massachusetts, a
state with 1/3 of the Atlantic Coast population. We also are responsible for
20% of the state’s American Oystercatchers, and 40% of its Least Terns.
Since 1986, Piping Plovers have rebounded from 135 pairs to
While the Cornell study showed shorebirds declining on a
continental scale, conservationists in Massachusetts have known that shorebirds
were in trouble since the middle of the last century. That’s why Mass Audubon
developed our Coastal
Waterbird Program to protect shorebirds through management, conservation,
policy development, and education.
In the past year alone, Mass Audubon petitioned for three
species to receive special legal protections from the state: Eastern
Meadowlarks, Saltmarsh Sparrows, and American Kestrels. These petitions were
based on our own monitoring of these species’ populations, which are in
particular trouble and require intervention, as well as growing consensus among
We also speak up when legal frameworks for protecting birds are under attack. The rollback of the Migratory Bird Treaty Act last year was a major setback for bird conservation, and we spoke up.
In addition to collecting data on bird-window collisions, Mass Audubon’s Avian Collision Team also generates many good stories that range from hopeful, to tragic, to simply strange. While most of the birds our volunteers found were dead, some were nursed back to health at the Tufts Wildlife Clinic. What follows is an account of one window-struck Chestnut-sided Warbler (Setophaga pensylvanica) that proved to be an emotional roller coaster for our project coordinators.
Part I: The warbler is alive
A dedicated ACT volunteer called up about a handful of window-struck birds outside a building facing the Boston Public Garden. Most were dead, but for a single Chestnut-sided Warbler. It was apparently sitting on the curb, visibly breathing, but injured. The volunteer was a little shaken up. Since they didn’t have a net or tools to safely catch the bird, I advised them to wait to see if the bird could fly off on its own before trying to catch it.
Part II: The warbler is dead
A few minutes later, the volunteer called back– sounding
even more shaken. The bird had flown away, but just as it lifted off, it was
caught in a gust of wind from a passing car and was struck by the fender. From
the volunteer’s description, the bird was truly lifeless. The volunteer said
they would take the carcass back to their freezer and eventually bring it to
the Harvard zoology museum, where we had been depositing specimens for
Part III: The warbler is alive, again
“It’s alive!” were the first words out of the volunteer’s
mouth on our third phone call within a half-hour. “The bag started moving!”
Stunned birds can truly appear lifeless, and in fact, many birds
that hit windows are stunned, concussed, or go into shock before eventually
shaking themselves off and flying away. But just because a bird can fly doesn’t
mean it’s healthy. A broken clavicle or corocoid bone allows birds to make
short flights, but prevents them from gaining altitude, halting their migration
and making them an easy meal for predators. Any bird found stunned from a
building impact is a good candidate for treatment at a wildlife care center.
The volunteer met Mass Audubon staff at a nearby T station to hand off the
bird, which was taken to Tufts Wildlife Clinic.
Part IV: The warbler is dead. Again.
The Tufts clinic graciously provides every animal with a
case number, so its finder can call up to check on its condition.
While the bird was initially given an optimistic prognosis,
we learned a few days after dropping it off that it had suffered untreatable
head trauma. The bird had died.
While healthy bird populations naturally fluctuate enough to
practically erase the effect of one birds’ death, there is no harm in trying to
save individual lives. Naturally, most volunteers prefer to put in the extra
effort involved in helping injured birds than leave them to die from an
indirectly human-inflicted injury. It was sad not to be able to save this
warbler, but we did successfully release a number of other birds, including
Brown Creepers, Song Sparrows, Ovenbirds and Common Yellowthroats.
If you want to help monitor window collisions and ambulate injured birds, join Mass Audubon’s Avian Collision Team for its fall migration via this form!
Here’s an easy way for anyone living or working in Boston to
help migratory birds: help monitor window collisions!
Mass Audubon is
seeking new volunteers for the fall season of the Avian Collision Team
(ACT). ACT is an initiative to collect data on bird–building collisions, and to
rescue injured birds.
This spring, the team of birders, conservationists, and
other concerned citizens observed 115 birds across 38 species affected by
window strikes. This fall, and in coming seasons, we need to keep up the
momentum and grow our dataset.
Window collisions are an under–appreciated source of bird
mortality in the US, causing several hundred million
Birds struggle to distinguish reflections from reality, and
often strike glass windows that reflect the sky or nearby greenery. City lights
also confuse night-migrating birds, which use the stars to navigate, and which
often land near sources of light pollution. Many window strikes occur as birds
try to re-orient in the morning, after being drawn in to an unfamiliar concrete
The program runs from August 24–October 28 in downtown Boston.
Volunteers need to sign up for 1-4 weekly shifts, Saturday–Tuesday, that can
take place between 6-9am. Most shifts last around 30-60 minutes.
Volunteers walk predetermined routes through downtown Boston
to photograph or collect deceased specimens, fill out data sheets, and occasionally
rescue live birds. We’ll be holding volunteer trainings on August 11, 18, and
Carrying out ACT surveys can be an eye-opening experience,
between watching the city as it’s waking up, discovering seemingly out-of-place
warblers, buntings, and vireos, and occasionally saving the life of an errant,
injured migrant. And once you’ve found your first few birds, a collector’s
instinct sometimes kicks in, making the search all the more engaging. It’s like
birding with a twist– a sense of urgency, purpose, and sometimes, a touch of
Since mid-April, a team of Mass Audubon volunteers has
combed the streets of downtown Boston in search of migratory birds killed by collisions
with windows. Here are some preliminary results of our first season running the
Avian Collision Team (ACT).
The first statistic that jumps out is the higher-than-expected number of live, injured birds found by our volunteers. Based on what we heard from New York, Chicago, and Toronto, we had told volunteers it was highly unlikely they’d be able to save any injured birds. This ended up being far from the truth! Here’s one video of a Brown Creeper that was well enough to be released after suffering non-life-threatening head trauma:
The Five “Hardest-hit” Species
Some patterns are also beginning to emerge in the species of
birds we’ve been finding. Here’s the full breakdown:
The five most frequently-encountered birds (in bold text
above) have something in common: they’re all low-flying migratory species, and
they’re relatively common. Certain buildings also seemed to kill a
disproportionate number of birds that climb trees vertically, like woodpeckers,
nuthatches, Black-and-white Warblers, and Brown Creepers. Other cities have reported similar species profiles with an emphasis on common migratory birds that fly low and weakly.
The Bottom Line
A few dozen people surveying a thin slice of the city for an hour or so per week found 119 window-struck birds of 38 species.
Other cities report that certain seasons have up to four times the number of strikes than others. The wide variability of window strikes makes it difficult, after just one season, to make broad statements about how many birds die from collisions in Boston annually, or establish how Boston shapes up compared to other cities. That said, our numbers fall roughly into the range reported by similarly-sized programs in other cities, like Baltimore, Detroit, and New York.
After accounting for scavengers, industrious building cleaners, and low volunteer detection rates, it’s estimated that only 10-20% of window strikes on a given route are actually recorded. That makes our numbers all the more sobering, especially considering our volunteers covered less than 1/50th of the street area of Boston.
That said, window strikes by themselves may not drive bird declines in Massachusetts. Window strikes are an additional stressor, however, on top of a laundry list of human-caused threats to bird populations. In today’s world of climate change, habitat loss, and invasive species, every bird counts– which is why window strikes are worth understanding.
Cities Are Only Part of the Problem
Outside the study areas in Downtown Boston, our volunteers
reported many casualties even without focused searching. Their findings
emphasize what other studies already suggest: window strikes are at least as
much of an issue at single-family homes and low-rises as they are at tall urban
The good news is that there are lots of ways to make your
home or office windows bird-safe. Here are some tips:
Screens on windows are the cheapest and perhaps simplest option: they break up reflections and also provide a springy barrier that collision-bound birds can bounce off of.
Where screens are impossible,
consider buying or building an Acopian Bird Savers
(hanging lengths of bird-deterring string). Learn how to build your own here!
Window decals only work when spaced less than 2” apart vertically and 4” apart horizontally, but when used correctly, they’re another great option. Certain kinds are transparent to human eyes, so even narrowly-spaced ones won’t interrupt your view.
Installing UV-reflective patterned glass like Ornilux is extremely effective, and
by far the most discrete option– but also the most expensive.
Finally, turning unneeded lights off
at night helps conserve energy and avoid drawing birds into strike-prone areas.
(Disclaimer: Mass Audubon has no
affiliation with any of the above vendors).
Since mid-May, Jon Atwood has been collaborating with US Fish and Wildlife Service (USFWS) managers at the Silvio O. Conte National Fish & Wildlife Refuge in a study aimed at monitoring Barn Swallow use of an abandoned stable located on the refuge’s Fort River Division in Hadley, MA.
Barn Swallows Are Declining in Some Places and Increasing in Others—Why?
Barn Swallows, along with many other aerial insectivores, are showing serious population declines in many portions of their North American range. However, the causes of these declines are uncertain. Pesticide impacts associated with large-scale agriculture, reduction of flying insect populations, landscape conversions, habitat changes along the species’ migration pathways, unknown impacts on the species’ Central and South American wintering grounds, and loss of barns and similar structures that are often used as nesting sites have all been postulated as possible factors.
The question is complicated—Barn Swallows in the northern portions of their range are mostly declining, while those in the south and west are increasing. If there is a single explanation, presumably the “answer” needs to make sense throughout that extensive range—why are populations increasing in some areas but decreasing in others?
Understanding Barn Swallows in MA
In this year’s work in Hadley, our focus is on starting to understand the population dynamics of Barn Swallows nesting in this portion of the Connecticut River Valley. About 30 pairs of swallows have nested in the abandoned stable in the last few years, making this site one of the largest known colonies in Massachusetts. Unfortunately, as is often true of aging barns in New England’s agricultural landscape, the stables in Hadley are in serious disrepair, and the Fish and Wildlife Service has recommended that the building be taken down over a several year period, while simultaneously making efforts to attract the birds to alternative nesting sites.
Mass Audubon and USFWS are studying this situation to collect information that will help inform the policy decisions. This work includes regular censusing of nesting efforts in the stables and banding of nesting adults. At the end of the season we will issue a final report that details our findings, so stay tuned for more information.
Mass Audubon needs your help monitoring an underappreciated threat to migratory birds: window collisions. We’re looking for volunteers to collect data on bird-building collisions and rescue birds that survive a strike.
Window collisions are a surprisingly significant source of
bird mortality in the US, causing several hundred million
Birds struggle to distinguish reflections from reality, and
often strike glass windows that reflect the sky or nearby greenery. City lights
also confuse night-migrating birds, which use the stars to navigate, and which often
land near sources of light pollution. Many window strikes occur as birds try to
re-orient in the morning, after being drawn in to an unfamiliar concrete jungle.
How to Help
The Avian Collision Team (ACT) is a new volunteer initiative
to get as much data as we can about building strikes in Boston. We want to understand
the scale of the problem in Boston, where the trouble spots are, and which
species are most affected.
The program runs from April 13–June 4. Volunteers need to
sign up for 1-4 weekly shifts, Saturday–Tuesday, from 8 am to around 9 am.
We are looking for two kinds of volunteers:
volunteers who will walk predetermined routes to collect deceased specimens,
fill out data sheets, and occasionally rescue live birds.
2. Transport volunteers who can pick up specimens from monitors and bring them to a collection site at Harvard. Drivers will also bring occasional injured, live birds to Tufts Wildlife Clinic in Westborough as needed.
Similar programs have shown that in parts of some cities, there are practically no casualties. In others, certain buildings can kill a dozen birds a day during peak migration. Scientists have developed guidelines for what makes buildings especially dangerous to migrating birds, but they’re still pretty rough. The best way to know where and to what extent there’s a problem in Boston… is to check!
A recent study showed that Saltmarsh Sparrows choose nest sites based on past experiences. If a pair’s nest floods, for example, they’ll build their next on higher ground.
While this behavior might seem to show resilience to rising seas and climate change, the authors note that populations have still declined by over 75% since the 1980s.
In fact, nesting further away from the water a risky proposition for Saltmarsh Sparrows, and flooding is not the only threat to their nests. As with any species threatened by climate change, what appears to be a successful adaptation to environmental change often turns out to have unforeseen repercussions for the species.
Caught Between a Fox and a Hard Place
Nesting further from the high-tide mark comes with trade-offs. Nests over drier ground are most vulnerable to predators, which are the second-greatest cause of nest failure in Saltmarsh Sparrows aside from flooding. Small carnivores like raccoons, foxes, and even snakes have been spotted feeding on Saltmarsh Sparrow chicks in nests far from the water’s edge.
Ticks, isopods, and other parasites also prefer drier nests.
Some tidal flooding deters
invertebrate pests, and may actually contribute to nestling survival
as long as the nest isn’t completely inundated.
Nests are most likely to be successful in a narrow band near
the high-tide mark where they are safe from predators, parasites, and flooding.
Researchers found that Saltmarsh Sparrows that lost their nests to predators
would re-nest closer to the waters’ edge, just as birds with flooded nests
would move to higher ground. But as increasingly severe storms now regularly
push spring tides past their normal height, they wash over what was once the
“sweet spot” between safety from predators and safety from flooding.
So, even though Saltmarsh Sparrows adjust their behavior to manage risks, they’re still only resilient to mild disruptions like steady and gradual sea level rise. Regularly-occurring extreme floods, coupled with
Saltmarsh Sparrows are in Trouble
Climate threats to Saltmarsh Sparrows are borne out by the data. Their population is currently around 30,000 birds– half of what it was in 2010, and a shadow of the original population of 250,000. They continue to decline at around 9% annually nationwide, but in Massachusetts, careful management of saltmarshes has kept their numbers comparatively stable.
Climate change is not the only issue facing Saltmarsh Sparrows. Over 1/3 of Massachusetts’ coastal wetlands have been developed. Dikes, railways, and other infrastructure disrupts the drainage of many remaining saltmarshes, raising the threshold for flooding but causing them to retain floodwaters for longer periods.
Mass Audubon continues to monitor Saltmarsh Sparrows in Massachusetts and advocate for the species, including submitting a proposal to list them as an Endangered species at the state level in 2017.
For tips on combating climate change, find out how to reduce your carbon footprint. For more information on Saltmarsh Sparrows, feel free to ask us a question in the comments!
Note: this post contains an image of a dead Bald Eagle that some readers may find graphic.
Most rat poisons kill more than rats—they also pose a fatal threat to birds of prey. This topic recently made the news after a Bald Eagle on Cape Cod died of what appears to be rodenticide poisoning. The tragic story was picked up by severalnewspapers, and went locally viral on facebook.
This issue should not only get attention when a culturally iconic species like a Bald Eagle dies. Nearly every raptor species is vulnerable to rodenticide poisoning, from Eastern Screech-Owls to Red-tailed Hawks.
In fact, rodenticide poisoning is shockingly widespread. In one study, 86% of all raptors at a Massachusetts wildlife hospital tested positive for exposure to rat poison.
Second-generation rodenticides: the worst of a bad bunch
The EPA recently banned a class of rat poisons called second-generation anticoagulants from the consumer market, but licensed exterminators are still allowed to deploy them. The ban came about because of the 10,000 children annually admitted to emergency rooms for rat poison exposure. The ban certainly helps limit accidental ingestion by humans, but unfortunately doesn’t do much to prevent birds from eating poisoned rodents.
Second-generation anticoagulants don’t kill rodents immediately. While these rodenticides can kill rats with a single dose (which is why many consumers prefer them), poisoned rats can still live for a few days and continue eating poisoned bait. This delay means that rats can ingest enough poison to kill a much larger animal by the time they finally succumb. While any rodenticide can kill a raptor, second-generation anticoagulants are the most dangerous.
The aforementioned Bald Eagle on Cape Cod likely fell victim to this class of rodenticide. While vets at the Cape Wildlife Center are still waiting for test results to come back, the eagle was bleeding heavily, and its blood failed to form scabs or clots—a nearly sure sign of anticoagulant poisoning.
This Bald Eagle was admitted to Cape Wildlife Center, but sadly didn’t make it. Photo courtesy of Cape Wildlife Center.
Rats are a human-made problem
Native to Eurasia, brown rats have colonized much of the globe and become the most common urban rodent worldwide. These rats were among the first human-assisted invasive species, living aboard ships and rapidly spreading to other continents as early as the 15th century, much to the detriment of countless sensitive ecosystems. Rats and other rodents especially wreak havoc on species found only on small islands, and have driven several seabird species to extinction.
Rat populations are on the rise, and towns are struggling to keep up (the town of Belmont even had to close a city park over a recent rat infestation). Rodent control is sometimes critical to the health of a city or an ecosystem—so what are some poison-free ways to prevent or control rodent problems?
(Don’t) pick your poison
Prevention is the best cure for rodent problems. Rodent infestations only occur when there’s an easy source of food. Make sure your trash cans are scavenger-proof, cover vegetable gardens with net or wire, attach tree guards to the trunks of fruit trees.
Limit access to shelter and hiding places that appeal to rodents. Seal up holes in your attic, basement, crawl spaces, and shed, and remove tree limbs within three feet of your roof.
Consider alternatives to poison. The Tufts Wildlife Clinic points out, “People often believe poisons are more humane than snap traps, but an animal bleeding to death is neither quick nor especially humane.”
If a rodent problem has gotten out of hand and you choose to use an exterminator, try to pick one that practices “integrated pest management”— a multi-pronged approach that avoids chemical control methods.
Finally, call your town or city hall and ask how the local government addresses rodent control. Suggest eliminating rat poison if it hasn’t been done already!